Method for the manufacture of packing containers and an arrangement for the realization of the method

Abstract

The invention relates to a method for the manufacture by means of shrink-forming of a packing container of orientation-stretched laminate comprising polyester and aluminium foil, the laminate being formed to a tube (14) and subsequently being made to shrink over a mandrel (10,28) to the intended shape.

We claim: 
     
       1. A method of manufacturing a container from a laminated web having a base layer of orientation-stretched polyester, a layer of metal foil, and at least one surface layer of glycol-modified polyester adjacent said base layer, said metal foil providing a gas barrier, said method comprising the steps of: providing a recess in said layer of metal foil along a first edge region of said web;   forming said web into a tubular element with said first edge region and another edge region of said web overlapping such that said layer of metal foil of said other edge region is separated from said first edge region by said base and surface layers of said other edge region;   bonding said overlapped first and other edge regions; and   plastically deforming said tubular element.   
     
     
       2. The method in accordance with claim 1, wherein said layer of metal foil is formed from aluminum. 
     
     
       3. The method in accordance with claim 2, wherein said aluminum foil is formed approximately 5/1000 mm in thickness. 
     
     
       4. The method in accordance with claim 1, wherein said bonding step includes thermal fusing of said edge regions. 
     
     
       5. The method in accordance with claim 1, wherein said bonding step includes extruding a strand of glycol-modified polyester between said edge regions and pressing said edge regions together. 
     
     
       6. The method in accordance with claim 1, wherein said plastically deforming step includes shrinking the tubular element with heat. 
     
     
       7. The method according to claim 6, wherein the method further comprises the step of covering a tubular end of the container in a tight manner with a metal disc fitted by beading. 
     
     
       8. The method according to claim 7, wherein the method further comprises the steps of forming an inwardly turned flange at another tubular end of the container and bonding to said flange a disc of the same material as the container with heat and pressure. 
     
     
       9. The method in accordance with claim 1, wherein said laminated web also has a second surface layer of glycol-modified polyester, said layer of metal foil being intermediate of said base layer and said second surface layer.